1. Field of the Invention
The present invention relates to a device which may prevent the upper pin tumblers of a lock from falling during change of a lock core in the lock.
2. Description of the Related Art
Taiwan Patent Laid-Open No. 163799 discloses a door lock with a changeable lock core in which the upper and lower pin tumblers can be changed in the case that the lower pin tumblers are worn due to a long-term usage or the key is lost. It is found proper to change the lower pin tumblers only, yet the upper pin tumblers may fall due to gravity during change of the lower pin tumblers. As a result, troublesome re-assembly of the upper pin tumblers and springs are required. The present invention is intended to provide a device to solve this problem.